极地运输船在碎冰区航行时会不断与海冰发生碰撞，致使内部产生周期性损伤，加剧了船体结构的疲劳问题。为此，本文建立一种基于离散元-有限元（DEM-FEM）的碎冰区航行船舶冰致疲劳损伤评估方法。首先，根据实际海冰分布，构造出一种混合海冰模型和数值碎冰航道。利用离散元法（DEM）计算出船体-碎冰碰撞下的冰载荷时历。将冰载荷时历施加到船体上，利用有限元法（FEM）计算出各疲劳子工况下的热点应力时历。采用改进四峰谷值雨流计数法统计热点应力时历的应力水平，基于线性累积损伤准则的S-N曲线法计算出各热点总的疲劳损伤度。最后，将本方法的计算结果与LR规范算法的结果进行对比分析，验证该方法的适用性。本方法可为碎冰区航行船舶的冰致疲劳损伤评估提供一定参考。
Polar transport vessels are subjected to repeated collisions with sea ice while navigating through broken ice fields, resulting in cyclic structural damage accumulation and exacerbated fatigue issues. A coupled discrete element-finite element (DEM-FEM) approach is proposed to evaluate ice-induced fatigue damage for ships operating in broken ice seas. A mixed sea ice model and numerical crushed ice channel representing actual ice conditions are first generated. Ice loads acting on the ship hull during interactions with sea ice are computed using the discrete element method (DEM). These ice load time histories are applied as dynamic loading in finite element method (FEM) analyses of the ship hull structure. FEM analyses produce hotspot stress time histories for various fatigue loading scenarios. The stress levels of the stress time histories were counted using the improved four-peak-valley rain-flow counting method, and the total fatigue damage of the hotspot was calculated by the S-N curve method based on the linear cumulative damage criterion. Finally, the results from the proposed method are compared with those from the LR′s specification approach to verify its applicability. This method can provide a reference for the assessment of ice-induced fatigue damage of ships navigating in the broken ice fields.
2024,46(12): 64-68 收稿日期：2023-08-04
DOI：10.3404/j.issn.1672-7649.2024.12.011
分类号：U661.4
基金项目：江苏省高等学校自然科学研究项目（23KJD580004）；南通市科技计划项目（JCZ20183）
作者简介：周陈炎(1993-),男,硕士,讲师,研究方向为船舶结构可靠性分析
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